A121160 Number of spiro bicyclic skeletons with n carbon atoms (see Parks et al. for precise definition).

1, 1, 6, 12, 43, 106, 322, 864, 2483, 6829, 19226, 53293, 148866, 413501, 1151506, 3200184, 8901478, 24742852, 68800520, 191275736, 531888416

Offset

5,3

Links

Table of n, a(n) for n=5..25.

Camden A. Parks and James B. Hendrickson, Enumeration of monocyclic and bicyclic carbon skeletons, J. Chem. Inf. Comput. Sci., vol. 31, 334-339 (1991).

Crossrefs

Sequence in context: A120471 A219522 A034529 * A105863 A052904 A106692

Adjacent sequences: A121157 A121158 A121159 * A121161 A121162 A121163

Keyword

nonn,more

Author

Parthasarathy Nambi, Aug 13 2006

Extensions

More terms from N. J. A. Sloane, Aug 27 2006

Status

approved